U.S. Pat. No. 7,467,764 to Hintzman discusses certain conventional emergency evacuation slide assemblies. As noted in the Hintzman patent:                Door-mounted emergency evacuation slides are typically contained within an enclosure mounted to the interior surface of the aircraft exit door. Opening of the door in the “armed” position causes the slide to be pulled downward out of the enclosure into a position immediately outboard of and below the door exit opening. The evacuation slide is then rapidly inflated to form a structure sufficiently rigid to enable the airline passengers to escape.See Hintzman, col. 1, 11. 14-21. The contents of the Hintzman patent are incorporated herein in their entirety by this reference.        
Gravity alone usually supplies sufficient force to position a slide pack clear of the opening door. Thus, conventional evacuation systems require no additional assistive force to deploy slide packs from their enclosures as associated doors open. However, for doors configured for rapid opening (i.e. having rotational speeds generally exceeding 1.2 radians per second), gravity may not cause the slide packs to fall downward sufficiently quickly to avoid being dragged forward (outward) together with their enclosures so as to jam the doors or twist undesirably during deployment.